Polymer-coated fabrics are flexible composite materials, comprising the coating (polymer layer) and the substrate (fabric layer), adhered together through a specific coating process. The polymer coating imparts properties on the fabric, such as printing of graphics, impermeability to dust particles, liquids, and gases. The polymer coating can also improve existing physical properties, such as tear and abrasion resistance. The fabric component generally determines the tear and tensile strength, elongation and dimensional stability. However, many properties are determined by a combination of both these components. The base-fabric and the polymer must be carefully selected, by a thorough consideration of the properties required in the finished article.
Radio frequency (RF) weldability and excellent Flame Retardancy are required for many of coated fabric applications. The flexible PVC (polyvinyl chloride) is a common coating material for coated fabric applications, due to the Excellent RF weldability and inherent flame retardancy. Vinyl (PVC) coated polyester is the most common material used on the market today for various applications. Other compositions are described as follows.
International Publication No. WO2013/096705 discloses a method of forming a polyolefin-based article that includes the following: (a) incorporating, into a polyolefin formulation, a filler that is capable of being excited by a high frequency electromagnetic field; (b) forming a substrate from the polyolefin formulation, the substrate having at least one surface; and (c) subjecting the surface of the polyolefin substrate to the high frequency electromagnetic field, under conditions, such that the substrate is welded to a second surface of the polyolefin substrate, or to a surface of a second polyolefin substrate, to form a polyolefin-based article. The polyolefin formulation comprises a zeolite that is ion exchanged with sodium, calcium, or potassium, in an amount of at least five weight percent, based on weight of the polyolefin formulation; and a base polymer selected from the group consisting of the following: (a) a homogeneously branched, linear or substantially linear ethylene/α-olefin copolymer having a density from 0.865 to 0.905 grams per cubic centimeter, and a melt index (measured at 190° C. at 2.13 kilograms) from 0.5 to 30 grams per 10 minutes, (b) a homogeneously branched propylene/α-olefin copolymer having a density from 0.863 to 0.885 grams per cubic centimeter, and a melt flow rate (measured at 230° C. at 2.13 kilograms) from 2 to 30 grams per 10 minutes, or (c) a combination thereof; and where the base polymer has a melting temperature below 100° C. The polyolefin substrate exhibits a cohesive welding failure and a weld strength, for a 10 mil (0.254 millimeter) thickness, that is greater than 7 pounds per inch (1.23 Newtons per millimeter), at a welding time of less than, or equal to, six seconds, to form a polyolefin-based article.
U.S. Pat. No. 3,336,173 discloses the blends of polyolefins and fiber-forming polymeric carbonamide, to form an electronic-weldable fabric. U.S. Pat. No. 5,627,223 discloses a composition comprising a polyolefin, a thermoplastic starch, and a coupling agent (for example, an ionic compound) to produce a high-frequency-welded article. U.S. Pat. No. 6,100,335 discloses polymeric compositions based on blends of propylene polymer, ethylene-vinyl acetate copolymer (EVA), and organic peroxide, for use for high-frequency weldable sheets.
U.S. Publication 2004/0077791 discloses a high-frequency weldable, thermoplastic rubber composition comprising the following: (A) a thermoplastic rubber comprising (i) a rubber; and (ii) a thermoplastic polyolefin homopolymer or copolymer; and (B) a polar-modifier, in an amount effective to render the thermoplastic rubber composition high-frequency weldable, and wherein the polar modifier is selected from the group consisting of the following: (i) thermoplastic polyurethane resins in an amount of at least about 25 wt %, (ii) chlorinated polyolefin resins, (iii) copolymers of ethylene and vinyl acetate, (iv) terpolymer of styrene, butadiene and acrylonitrile, or (v) mixtures thereof.
U.S. Pat. No. 5,399,396 discloses RF-weldable multi-layered films, which have a barrier layer and a seal layer. The composition of the seal polymer layer is polymer derived of ethylene and ethylenically unsaturated ester (vinyl acetate (VA) or acrylate). The seal layer has an anti-block matted surface. U.S. Pat. No. 5,135,785 discloses pouches and films which contain of at least one barrier layer of a polyolefin, and at least one seal layer of ethylene-vinyl acetate. The seal layers are disclosed as weldable using radio frequency welding.
International Publication No. WO 93/24568 discloses a polymer article prepared by the process comprising the steps of: (1) blending polymer composition comprising the following: (A) at least one ethylene vinyl acetate copolymer, (B) at least one propylene ethylene copolymer, and (C) (1) from about 0.01% to about 5%, by weight, of a cross-linking agent, (2) from about 0.1% to about 35%, by weight, of one or more polymers selected from: (i) at least one co-, or terpolymer of at least one vinyl aromatic compound, (ii) at least one co-, or terpolymer of an alpha-olefin, and at least one monomer selected from the group consisting of an acrylic acid, an acrylic ester, a vinyl silane, and a vinyl alcohol, (iii) at least one polyolefin other than a propylene homopolymer or a propylene-ethylene copolymer, (iv) at least one polyetheramide block copolymer, (v) at least one ionomer, (vi) at least one oxidized polyolefin wax, or mixtures of (1) or (2); and forming the polymer composition into the article. The polymer articles are disclosed as being radio frequency weldable.
JP10219048A (English Abstract) discloses a polypropylene composition comprising the following: (A) 0.1-5 pts.wt. of metal oxide particles, (B) 0.1-5 pts.wt. of ion-substituted zeolite and (C) 100 pts.wt. of polypropylene. The composition is disclosed as having high frequency welding property, an antibacterial property, and a UV light-shielding property, and capable of exhibiting excellent light transmittance, by adding ultrafine zeolite particles and ultrafine metal oxide particles as crystal nucleus-forming agents to polypropylene resin.
WO2002/088229 discloses an HF responsive composition comprising the following: (A) a molecular sieve material, and (B) at least one interpolymer comprising (i) polymer units derived from at least one aliphatic olefin monomer having from 2 to 20 carbon atoms; and (ii) polymer units derived from (a) at least one vinyl or vinylidene aromatic monomer, or (b) from at least one sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (c) from a combination of at least one vinyl or vinylidene aromatic monomer and at least one sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, and optionally (d) polymer units derived from at least one ethylenically unsaturated polymerizable monomer, other than that derived from (a), (b) or (c).
There is an increasing need to replace materials that are perceived as less “environmentally safe,” like PVC, with those that are more “environmentally safe,” such as olefin-based polymers. However, olefin-based polymers are typically non-polar polymers, and therefore, are not radio frequency active. Also olefin-based polymers typically have high fuel numbers, which makes them very flammable. There is a further need to develop olefin-based compositions which are RF weldable and have good flame retardancy (for example, can pass a stringent flame retardancy test such as NFPA 701). These needs have been met by the following invention.